Field
Exemplary embodiments relate to a touch panel including a touch sensor and a driving method thereof.
Discussion of the Background
Flat panel displays (FPDs) such as an organic light emitting diode display (OLED), a liquid crystal display (LCD), and an electrophoretic display (EPD) include a display panel having an electrode to which an electrical signal is applied, and an electro-optical active layer. Recently, display devices including a touch sensing function have been developed to allow interaction with an observer in addition to the image displaying function.
The touch sensing function is used to determine touch information such as whether an object has approached or touched a screen and a location of the touch by sensing changes in pressure, charge, light, and the like which are applied to the screen when the user writes text or draws figures by approaching or touching the screen using a finger or a touch pen. The display device may receive an image signal based on the contact information.
The touch sensing function may be realized by a touch sensor including a touch electrode. A panel on which the touch sensor is formed is typically called a touch panel (or a touch sensor panel or a touch screen panel), and a display panel having the touch sensor function may also be called a touch panel.
Touch panels may be classified according to the method for sensing a touch, such as a resistive type or a capacitive type.
The resistive touch panel has a configuration in which a material including a resistance component is coated on a substrate made of glass or transparent plastic and a polyester film is formed thereon. Insulating rods are installed at uniform distances apart so as to not touch one another between two surfaces of the resistive touch panel. Resistance is changed when the touch panel is touched, and a voltage change is detected to sense a touched position. The resistive touch panel has a drawback of failing to sense a weak pressure.
Conversely, regarding the capacitance touch panel, an electrode is formed on respective sides or one side of a substrate made of glass or transparent plastic, a voltage is applied between two electrodes, and an amount of capacitance between the two electrodes changes when an object such as a finger contacts the touch panel to sense a touching point.
Regarding the capacitance touch panel, a plurality of touch electrodes are connected to each other so that they may form a plurality of touch electrode rows and a plurality of touch electrode columns insulated from each other, and a driving signal is applied to the touch electrode rows and the touch electrode columns through touch signal lines. A touch sensor may drive the touch electrode rows and the touch electrode columns by using mutual capacitance formed between the touch electrode rows and the touch electrode columns, or may drive the same by using self-capacitance formed by the respective touch electrode rows and the touch electrode columns.
Further, the touch electrode rows and the touch electrode columns may be formed as a single layer or a plurality of layers. When formed to be a single layer, compared to the case of being formed as a plurality of layers, they have a relatively simple configuration so the touch panel may be structured with a less cost, but the touch signal lines are formed by the number of the touch electrodes and an area of the touch electrodes is inevitably restricted by the region occupied by the touch signal lines so touch sensitivity may also be restricted.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the inventive concept and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.